DROPPING THINGS

M. E. W. North, 1948, Ibis, p. 138-41 (lammergeier). E. Jaeger, 1951, Condor, 53, p. 207 (sparrow).

LEARNING BY BIRDS

A. L. Rand, 1941, Bull. Amer. Mus. Nat. Hist., Vol. 78, p. 222 (thrasher). A. L. Rand, 1942, Bull. Amer. Mus. Nat. Hist., Vol. 79, p. 518 (blue jay).

CAN BIRDS COUNT?

Bird-banding, 1940, Vol. 11, p. 121 (summary various experiments).

COURTSHIP FEEDING

D. Lack, 1940, Auk, Vol. 57, p. 169 (courtship feeding).

THEY TURNED THE TABLES

A. C. Bent, 1926, U. S. Natl. Mus. Bull. 135, p. 109 (great blue heron). W. P. Baldwin, 1946, Auk, Vol. 63, p. 589 (oyster catcher). G. Mackay, 1929, Auk, 46, p. 123 (goldfinch). D. Bannerman, 1936, Birds Tropical West Africa, Vol. 4, p. 244 (dusky flycatcher).